Sorry for the delayed response. As suggested by Mylenium earlier, this feature is not available within the app.
I'd suggest sharing a feature request on Adobe Illustrator UserVoice. This forum is monitored by product team and they might look into it for upcoming releases.
Hope it helps.
There is no such thing. Simply don't share them if you don't want other people to use your stuff. Otherwise you have to come to terms that anything can be copied and remade once it's out there on the Internet. At best you can make things a lot more difficult by e.g. rasterizing your cvector artworks as pixels, but that won't stop anyone from re-drawing/ tracing it or any such thing.